A typical railroad hopper car includes an elongated frame supported toward opposite ends on trucks for movement over rails. A hopper is mounted on the frame and includes a plurality of open bottom chutes from which commodity within the hopper is gravitationally discharged. To control the gravitational flow of material from the hopper, the opening at the bottom of each chute has a gate assembly arranged in general registry therewith.
Each gate assembly includes a rigid frame defining a discharge opening arranged in registry with the opening at the bottom of each chute on the hopper. A door is slidably positioned on the frame for a generally horizontal range of movements. More specifically, the door is mounted on the frame for sliding movements between a closed position, wherein the door closes the discharge opening, and an open position. In the open position, the door is disposed to one side of the opening. As will be appreciated by those skilled in the art, commodity within the hopper exerts or places an appreciable columnar load on the slide door when the slide door is in the closed position.
On many gate assemblies, movement of the door between open and closed positions is effected by an operating shaft assembly carried by the frame of the gate assembly for rotation about a fixed axis. The operating shaft assembly is operably coupled to the slide door of the gate assembly. The operating shaft assembly typically includes an elongated operating shaft which is supported at opposed ends by capstans. In one form, a rack and pinion assembly converts rotational movements of the operating shaft assembly into linear displacement of the door depending upon the direction of rotation of the operating shaft assembly.
Each capstan of the operating shaft assembly is typically configured to receive either an elongated bar or a free end of a high-powered torque driver. In one instance, the elongated bar is inserted through the capstan and the capstan is rotated to effect movement of the slide door. In the other instance, the free end of the high-powered torque driver is inserted into a free and open end of the capstan and the driver is operated to forcibly rotate the capstan and thereby move the slide door, depending upon the direction the door opener mechanism, between closed and open positions.
As will be appreciated by those skilled in the art, time is typically of the essence regarding unloading of a railroad hopper car. As such, in many railroad hopper car unloading situations, the railcar does not come to a complete stop during the unloading process. Accordingly, and in those situations when an elongated bar is used to rotate the operating shaft assembly to effect opening of the slide door, an operator needs to walk alongside the railcar to effect rotation of the operating shaft. Of course, the elongated bar is usually relocated several times with respect to the capstan to effect sufficient rotation of the operating shaft assembly to move the slide door from a closed position to an open position. Requiring an operator to walk alongside a moving railcar while having to repeatedly locate, insert, rotate, remove, relocate, reinsert and again rotate the elongated bar relative to an opening in a capstan can and often does prove to be problematic for all concerned.
To facilitate movements of the high-powered torque driver into operable engagement with the free end of the capstan, it is common for such drivers to be mounted on wheels. As such, the driver can be moved toward and away from the gate as required. As the railcar continues to move during the unloading process, however, the driver is problematically dragged along in a direction not in line with the wheels on the driver.
Alternatively, the driver is mounted on wheels which allow the high-powered torque driver to move along a path extending generally parallel with the direction of movements of the railcar. In this alternative arrangement, the free or distal end of the driver is movable toward and away from the free end of the capstan.
With either high-powered torque driver arrangement, the free or distal end of the driver tends to wear and result in significant damage to the open end of the capstan. Of course, when the free and open end of the capstan becomes worn, use of the high-powered torque driver is no longer feasible whereby requiring manual use of the elongated bar to move the slide door accompanied by the problems associated therewith.
Thus, there is need and continuing desire for a mechanism for operating a railcar discharge gate assembly which is carried by and moves with the railcar and is designed to eliminate many of the known problems associated with operating a slide door of a railcar gate assembly between closed and open positions.